1. Field of the Invention
This invention relates to electronic timepiece operating by the power supply of chargeable battery, and to checking method for the timepiece.
2. Description of the Related Art
There are a variety of portable electronic timepieces such as wristwatches and electrical clocks. Some of these timepieces have chargeable power source such as chargeable batteries or large-capacitance capacitors. And in some others, battery units are constructed as removable unit. In these timepieces, time-keeping units and digital (or analog) displaying units for displaying time conduct operation by using the electrical power stored on the batteries.
FIG. 11 shows a flowchart showing one example of manufacturing process and checking process for timepiece with battery and charging means for the battery.
As for FIG. 11, discharging step (step A101) is done before manufacturing electrical timepiece.
In this discharging step, by using an external discharging circuit, for example as shown in FIG. 12, the battery is discharged alone. In the external discharging circuit 100 shown in FIG. 12, a plurality of (n piece of) batteries from BA1 to BAn are placed on a battery placing section 101. Each battery from BA1 to BAn is connected in series to a resister from R1 to Rn respectively. A sink type constant voltage power source 102 is connected in parallel to each of the above series-connected resisters and batteries. By the above configured external discharging circuit 100, batteries from BA1 to BAn are discharged at the same time. In this case, the number of installation terminals for the batteries in the external discharging circuit 100 have to be enough for the number of batteries discharged at the same time.
After this battery discharging step (step A101), an assembling step (step A102) and an exterior installation step (step A103) is conducted. Then a battery charging step (step A104) is conducted.
In this charging step, quality of charging function of the battery is examined, and enough electrical energy for the electrical timepiece operation in the next step of an operation checking step (step A105) is stored in the battery. Charging is conducted in the following way. For example, for a timepiece with a rotating type generator, giving a vibration to the timepiece moves an oscillation weight in the rotating type generator of the timepiece. A kinetic energy generated in the oscillation weight in this process is converted by the generator into electrical energy, and then the electrical energy is stored in the battery. And in other type of timepiece such as with solar panel, generation is conducted by the solar panel, and the generated electrical energy is stored in the battery. And yet in other type of timepiece, it is possible to use for generation an inductive energy in accordance with an exterior radio wave or a magnetic force, and to charge the battery.
Confirmation of a charging state is conducted in the following way. In the charging step, an operator puts a charging state display function into action, the charging state display function being installed in the timepiece. And the operator checks the displaying state of the timepiece, and confirms whether or not the charging the battery is over.
The battery discharging step (step A101) mentioned above is done in order to, at this charging step, control an accuracy of battery voltage inspection within a certain range.
In the operation checking step (step A105), a quality verification for the electrical timepiece is conducted. This quality verification comprises timepiece operation verification in high and cold temperature. In detail, in the operation checking step, at around 60 degree centigrade of high temperature atmosphere and around minus 10 degree centigrade of low temperature atmosphere, a trial operation extending several hours or several tens of hours is conducted. In this trial operation period, a stoppage and a delay of time display is checked. And by confirming a continuous discharging time of the battery after the trial operation, a quality confirmation (judgment) is conducted.
After the operation checking step, a shipment checking step (step A106) with an exterior checking and a full-charging step (step A107) to full-charge the battery is conducted, then the timepiece is shipped (step A108).
Incidentally, in the battery discharging step explained above, discharging the battery is conducted alone by using the external discharging circuit before the assembling. And discharging time requires from several to several tens of hours. Therefore, discharging circuit facility with enough number of, for example enough for one day production of timepiece, installation terminals for the batteries is necessary. Hence, this discharging method is not appropriate for a model produced on a massive scale.
And if, for example, after the shipment, an operation verification for discharging function is required, it is very difficult for the battery to be made on a certain discharging state without a discharging facility.
Moreover, there are several kind of battery. Even among lithium type battery, discharging character differs, for example, according to types of electrode as shown in FIG. 13. And chargeable battery has a characteristic of voltage recovery effect by which, after stopping discharging, voltage rises. Therefore battery voltage is unstable and becomes wide after discharging. This voltage dispersion after discharging causes a disadvantageous effect on the checking accuracy.
And in the charging step, for example, a charging state such as charging voltage is displayed by the amount of fast-forwarding movement of the analog second hand on the displaying section, by pushing a certain switch. In this case, external operation such as pushing a certain switch or the like is necessary to confirm the charging state. Hence an external input is required, and resulting in a problem of more operation process. And since confirmation is done by the amount of fast-forwarding movement of the analog second hand, if the amount of fast-forwarding movement is wrongly recognized, there is a possibility that checking result falls in a fault judgment.
And in the operation checking step, the quality verification for the electrical timepiece is conducted by checking the operation under a high and low temperature atmosphere. More precisely, by checking whether or not there is a stoppage (continuous time-keeping trouble) or a delay under the above condition, the quality verification of the timepiece is conducted. Therefore even when the trouble is detected in the timepiece, it is difficult to identify the cause of the trouble whether it is due to the motor drive unit or due to the battery.
In order to confirm that it is due to a motor drive trouble, it is required to examine even a gear train unit for driving hour, minute and second hand. And in order to do this examination, it is required to break the timepiece up by considerably fine detail. Hence, in order to prevent this complicated breaking up work and examination, there is a demand that distinction between the motor drive trouble and other factor be made as easy as possible. However, in the prior arts timepiece, it is difficult to make a distinction between the motor drive trouble and other factor.
And as for the motor drive trouble, as long as the motor is not apparently low quality, it is not possible to judge that the trouble is due to the motor. But, for example, there is somewhat low quality motor which under some temperature condition works and does not cause a delay. Ideally, this kind of motors should also be judged as motor problem. However it is difficult to make such a judgement.
By taking the above situation into considering, the object of the present invention is to provide an electrical timepiece with a checking function which, for example, in the timepiece manufacturing process enhances the checking accuracy and efficiency, and a checking method for the timepiece.